1. Field of the Invention
This invention relates in general to semiconductor devices and more specifically for techniques for bonding enclosures of a semiconductor device.
2. Description of the Related Art
With some types of semiconductor devices such as micro electrical mechanical system (MEMS) devices, it is desirable to seal the device (e.g. hermetically) for the device to perform properly over time. For example, with some types of MEMS accelerometers, it is desirable to seal the MEMS accelerometer in a chamber to prevent contamination of the moving parts of a MEMS accelerometer during subsequent processes.
One method for sealing a MEMS device is to bond a cap wafer to a second wafer that includes the MEMS device. The cap wafer and the second wafer form a cavity for the MEMS device. The cap wafer may include a lead glass frit located around the cavity that bonds to the second wafer under pressure and temperature.
What is needed is an improved technique for bonding two wafers together to seal a semiconductor device such as a MEMS device.
The use of the same reference symbols in different drawings indicates identical items unless otherwise noted. The Figures are not necessarily drawn to scale.